(72 days)
The Konan Specular Microscope XIV, Cellchek Plus, is a non-contact ophthalmic microscope, optical pachymeter, and camera intended for examination of the corneal endothelium and for measurement of the thickness of the cornea.
The Konan Specular Microscope XIV, CellChek Plus, is a non-contact ophthalmic microscope, optical pachymeter, and camera intended for examination of the corneal endothelium and for measurement of the thickness of the cornea. Cell counting and analysis programs are included, and allow for analysis of the cell distribution of the eye (the same analysis software present in the predicate device is also present in the modified device).
When photographing the corneal endothelium, the equipment performs the alignment and automatically focuses by capturing the reflected light from the patient's eye with the CCD camera. The device permits visual inspection and photography of the corneal endothelium and measurement of the corneal thickness without any object contacting the eye. It features focusing by means of infrared techniques, and computer-assisted cell counting and cell analysis capabilities. The computer functions are also used to aid in setting up the various features of the machine and to aid in photography. Photographic images are temporarily stored in the system's memory, and are preserved by using a printer.
Both the image of the corneal endothelium and the various computerized control functions are displayed on the touch screen.
The parts of the device that come into contact with a patient are the forehead rest and the chin rest. The head rest is comprised of Polytetrafluoroethylene (PTFE), which is known as Teflon®, and the material that comprises the chin rest is Acrylonitrile butadiene styrene (ABS).
Here's an analysis of the acceptance criteria and study that proves the device meets them, based on the provided text:
Device: Konan Specular Microscope XIV, Cellchek Plus
1. Table of Acceptance Criteria and Reported Device Performance
The provided text does not explicitly state "acceptance criteria" in a numerical or pass/fail format for the clinical study. Instead, it focuses on demonstrating the agreement and variability of different analysis methods (Manual, PC-Assist with redrawing, PC-Assist without redrawing, and Center) for Cell Density, Coefficient of Variation, and Percent Hexagonality. The implied acceptance is that the agreement and variability between these methods, particularly when compared to a 'Manual' or 'exact' method, are within acceptable ranges for clinical use, or comparable to the predicate device.
Since explicit numerical acceptance criteria are not given, the table below presents the reported performance metrics that would likely be evaluated against such criteria if they were defined. The goal of the study was to show substantial equivalence, suggesting that these values align with what is considered acceptable for the predicate device.
| Metric (Parameter) | Analysis Method | Reported Device Performance (Mean Difference / Lower 95% Limit / Upper 95% Limit) | Reported Device Performance (Correlation Coefficient R²) | Reported Device Performance (Standard Deviation within-image as % of mean) |
|---|---|---|---|---|
| Cell Density | Manual vs. PC-Assist (with redrawing) | 0.06 / -0.78 / 0.9 | 0.8719 | PC-Assist (with redrawing): 1.14 |
| Manual vs. PC-Assist (without redrawing) | 0.00 / -2.3 / 2.3 | 0.9813 | PC-Assist (without redrawing): 0.78 | |
| Manual vs. Center | 0.16 / -1.1 / 1.42 | 0.9636 | Center: 1.23 | |
| Center vs. PC-Assist (with redrawing) | -0.11 / -1.47 / 1.25 | 0.8544 | ||
| Center vs. PC-Assist (without redrawing) | -0.17 / 2.71 / 2.37 | 0.955 | ||
| Coefficient of Variation | Manual vs. PC-Assist (with redrawing) | 0.43 / -2.35 / 3.21 | 0.2709 | PC-Assist (with redrawing): 4.23 |
| Manual vs. PC-Assist (without redrawing) | 0.24 / -5.62 / 6.10 | 0.8185 | PC-Assist (without redrawing): 8.02 | |
| Manual vs. Center | -1.96 / -8.58 / 4.66 | 0.2041 | Center: 6.60 | |
| Center vs. PC-Assist (with redrawing) | 2.38 / -4.18 / 8.94 | 0.201 | ||
| Center vs. PC-Assist (without redrawing) | 2.18 / -4.18 / 8.94 | 0.2318 | ||
| Percent Hexagonality | Manual vs. PC-Assist (with redrawing) | -0.08 / -3.32 / 3.16 | 0.0006 | PC-Assist (with redrawing): 3.87 |
| Manual vs. PC-Assist (without redrawing) | 1.47 / -3.63 / 6.57 | 0.6659 | PC-Assist (without redrawing): 12.67 | |
| Manual vs. Center | -2.23 / -7.03 / 2.57 | 0.4307 | Center: 6.42 | |
| Center vs. PC-Assist (with redrawing) | 2.13 / -3.03 / 7.29 | 0.1846 | ||
| Center vs. PC-Assist (without redrawing) | 3.67 / -3.13 / 10.47 | 0.3811 |
Note from the text: "These tables indicate that cell density has a good correlation with the Manual Method (an exact method); the other parameters are only weakly-correlated, especially without redrawing." This serves as a qualitative acceptance criterion, indicating that strong correlation for cell density is considered important, while weaker correlation for other parameters might be acceptable depending on their clinical significance.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: 40 images (of eyes)
- Data Provenance: Not specified, but the study was performed using the Konan predicate device. It is a retrospective analysis of previously acquired images.
3. Number of Experts and Qualifications
- Number of Experts: 4 "classifiers" (referred to as a group)
- Qualifications: Not specified.
4. Adjudication Method for the Test Set
- Adjudication Method: Each of the 4 "classifiers" analyzed each image three times. The analyses were then used to calculate agreement and variability. There is no mention of a consensus process (e.g., 2+1, 3+1) to establish a single ground truth per image from disagreement among classifiers. Instead, the study assessed agreement between analysis methods and variability within each analysis method.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- Was an MRMC study done? No, not in the traditional sense of comparing human readers with and without AI assistance. This study focused on assessing agreement and variability between different analysis methods (Manual, PC-Assist, Center) and within each method by repeated readings from classifiers, all done using the predicate device's analysis capabilities. It was a comparison of analysis features, not a human vs. AI assistance study for diagnostic improvement.
- Effect size of human readers with AI vs. without AI assistance: Not applicable, as this was not the design of the study.
6. Standalone (Algorithm Only) Performance
- Was standalone performance done? The "PC-Assist" and "Center" methods represent algorithmic or automated analysis capabilities embedded within the device. Their performance characteristics (agreement, correlation, variability) are reported individually and in comparison to the "Manual" method. Therefore, the study did assess aspects of standalone algorithmic performance by evaluating these automated methods.
7. Type of Ground Truth Used
- Type of Ground Truth: The "Manual" method appears to be treated as an "exact method" or reference standard for comparison, particularly for cell density. The text states, "cell density has a good correlation with the Manual Method (an exact method)". This suggests that the ground truth for evaluating the automated methods was established by a manual analysis considered to be precise.
8. Sample Size for the Training Set
- Sample Size: Not specified. The document describes a clinical test but does not provide details about a training set for the device's algorithms. It's possible the algorithms were developed prior to this study and this study served as a validation.
9. How Ground Truth for the Training Set Was Established
- How Ground Truth Was Established: Not specified, as training set details are not provided.
§ 886.1850 AC-powered slitlamp biomicroscope.
(a)
Identification. An AC-powered slitlamp biomicroscope is an AC-powered device that is a microscope intended for use in eye examination that projects into a patient's eye through a control diaphragm a thin, intense beam of light.(b)
Classification. Class II (special controls). The device, when it is intended only for the visual examination of the anterior segment of the eye, is classified as Group 1 per FDA-recognized consensus standard ANSI Z80.36, does not provide any quantitative output, and is not intended for screening or automated diagnostic indications, is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 886.9.